When a stubborn window shade stays down, no matter how hard you tug on it to activate the spring that rolls it up, you need to increase the tension on the shade's internal spring mechanism inside the roller to get it to work. It's a quick adjustment, but you may have to repeat it until the shade's spring tension is just how you like it.
Test the Tension
Roll up the shade by hand so it is halfway up the window. It will be easier to handle in this position.
Remove the shade from its brackets. Grasp the shade at the roller and tilt it forward or back, depending on the flat pin's position in the slotted bracket. Lift it up and out.
Wind the shade manually back up onto the roller and set it back into the slotted bracket. Make certain that you roll it back onto the rod evenly and carefully. When it's not aligned correctly on the rod, it will not roll down or retract correctly.
Insert the shade back in the brackets.
Pull down on the shade gently to test if it has any tension. Verify that it retracts correctly and not uneven. Repeat the steps as necessary until the spring tension is the way you want it. Tugging on it can automatically tighten the internal spring mechanism to increase tension.
Uncoiled Spring Adjustment
Take the spring roller shade out of its brackets again if tugging on the shade to tension did not work or if the shade remains down. If the shade stays down and cannot be pulled back up, you may need to use pliers to rewind the spring located inside the hollow roller tube.
Roll up the shade manually again until it is halfway.
Grasp the pin on the spring side of the shade with the pair of pliers. Turn it counterclockwise until you feel the tension increase on the spring through the tool. Back off slightly to allow the pawl to hook onto the ratchet inside the metal end of the shade.
Replace the roller shade in the bracket again to test the shade's tension. Readjust to loosen or tighten the tension on the spring as necessary.
Too Tight Spring Release
Take the spring roller shade out of the brackets if there is still a problem with the tension. If the spring is wound too tightly, the roller shade will not operate correctly, either. It might be wound too tightly on the tube or pulled out, but will not spring back when you pull on the shade, preventing it from rolling up.
Grip the pin with the pliers and turn it clockwise to release the pawl which will relieve the tension on the spring. Let the pliers go quickly to release the tension.
Follow the steps to reset the tension for an uncoiled spring roller shade if there is now zero tension on the spring after it was released.